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Phosphite esters are typically prepared by treating phosphorus trichloride with an alcohol. For alkyl alcohols the displaced chloride ion can attack the phosphite, causing dealkylation to give a dialkylphosphite and an organochlorine compound. [1] [2] The overall reaction is as follows: PCl 3 + 3 C 2 H 5 OH → (C 2 H 5 O) 2 P(O)H + 2 HCl + C 2 ...
Solvents are often not used for this reaction, though there is precedent for the improvement of selectivity with its usage. [5] Phosphonites are generally more reactive than phosphite esters. They react to produce phosphinates. Heating is also required for the reaction, but pyrolysis of the ester to an acid is a common side reaction. The poor ...
Phosphites, sometimes called phosphite esters, have the general structure P(OR) 3 with oxidation state +3. Such species arise from the alcoholysis of phosphorus trichloride: PCl 3 + 3 ROH → P(OR) 3 + 3 HCl. The reaction is general, thus a vast number of such species are known.
This reaction is a variant of the Michael addition: CH 2 =CHCO 2 R + 3 H 3 PO 3 → (HO) 2 P(O)CH 2 CH 2 CO 2 R. In the Hirao coupling dialkyl phosphites (which can also be viewed as di-esters of phosphonic acid: (O=PH(OR) 2) undergo a palladium-catalyzed coupling reaction with an aryl halide to form a phosphonate.
It reacts with phenol to give triphenyl phosphite: 3 PhOH + PCl 3 → P(OPh) 3 + 3 HCl (Ph = C 6 H 5) Alcohols such as ethanol react similarly in the presence of a base such as a tertiary amine: [9] PCl 3 + 3 EtOH + 3 R 3 N → P(OEt) 3 + 3 R 3 NH + Cl −. With one equivalent of alcohol and in the absence of base, the first product is ...
Diethyl phosphite hydrolyzes to give phosphorous acid. Hydrogen chloride accelerates this conversion.: [2] Diethyl phosphite undergoes transesterification upon treating with an alcohol. For alcohols of high boiling points, the conversion can be driven by removal of ethanol: [8] (C 2 H 5 O) 2 P(O)H + 2 ROH → (RO) 2 P(O)H + 2 C 2 H 5 OH
The reaction mechanism of the Mitsunobu reaction is fairly complex. The identity of intermediates and the roles they play has been the subject of debate. Initially, the triphenyl phosphine (2) makes a nucleophilic attack upon diethyl azodicarboxylate (1) producing a betaine intermediate 3, which deprotonates the carboxylic acid (4) to form the ion pair 5.
The Abramov reaction is the related conversions of trialkyl to α-hydroxy phosphonates by the addition to carbonyl compounds. In terms of mechanism, the reaction involves attack of the nucleophilic phosphorus atom on the carbonyl carbon. [1] It was named after the Russian chemist Vasilii Semenovich Abramov (1904–1968) in 1957. [2]